A judge capped a 20-month legal battle on Tuesday by lifting an order preventing UC Berkeley from building a sports training center next to Memorial Stadium.

In her final judgment issued late Tuesday, Alameda County Superior Court Judge Barbara Miller wrote that the university had complied with the outstanding legal issues and could begin construction at the stadium's adjacent oak grove, where a handful of tree-sitting protesters have been roosting since December 2006.

"The university has now cleared the most significant legal hurdle," said UC Berkeley spokesman Dan Mogulof. "We're one giant step closer to being able to begin construction."

The judgment allows the plaintiffs, the California Oak Foundation and the Panoramic Hill neighborhood group, two days to appeal the ruling. The university has said it will not begin construction until the state Court of Appeal rules on the case, which could be as soon as next week.

The plaintiffs' attorney, Stephan Volker, said he would ask the appeals court to reverse Miller's decision and reinstate the injunction that prevents the university from constructing the sports facility.

The $125 million project violates state earthquake and environmental laws and must be resubmitted to the UC regents before being built, Volker wrote in his appeal.

"Whatever we have to do we will do to maintain the injunction," Volker said following a hearing Monday at the county courthouse in Hayward. "If the court takes a year to make a decision, the (injunction) will stay in place for a year."

The UC regents approved the training center in December 2006, intending to provide seismically safe and dramatically upgraded offices, locker rooms and training facilities for 13 varsity sports, including football. The city of Berkeley, oak tree advocates and neighbors sued to stop the project, saying it would bring development to the most inaccessible and seismically sensitive part of town and unnecessarily destroy the oak grove adjacent to the stadium.

Miller sided with the university on most issues. The university offered to drop two points she objected to: construction of a grade beam supporting the stadium's west wall and plans to host more non-football events at the 85-year-old landmark stadium.

The university has been eager to begin construction of the facility as football season nears. About 70,000 fans are expected at Memorial Stadium on Saturday for the Cal Bears' home opener against Michigan State.